Skip to main content
Blog

What is a Perc Test and Why is it Important?

By March 30, 2023No Comments
If you have ever looked at land or lots for sale, or considered building, you have probably heard of a perc test. There are many soil tests that need to be completed before building on a plot of land, and a perc test is one of the most common. So what is a perc test, and what does it mean?

What is a perc test used for?

Put simply, a percolation test (or perc test) measures the water absorption in the soil. This test is required in order to design a septic system for the building that is being planned. The percolation rate of the land surrounding a septic system is important in order to prevent flooding the septic system or polluting the groundwater.

There is a minimum and maximum percolation rate required for septic systems. If the soil does not “perc” within that range, it is unsafe to install a septic system and you will not get the necessary approval or permits for this vital step in the building process.

Perc tests are also helpful in measuring the flood risk for the land. This is especially important in the Southern Maryland region, which is surrounded by large bodies of water such as the Potomac River and Chesapeake Bay.

How is a perc test done?

Once it is determined that the soils on the land are suitable for septic development (by examining the texture and other variables), a perc test is completed by digging multiple test holes at varying depths. PVC pipes are then inserted into the test holes, and presoaked.

On the day of the perc test, the holes are filled with water to a measurable level. It is then measured how long it takes for the water to absorb, or percolate, into the soil. The rate is measured by volume and time, usually in cubic inches per minute.

It is important to note that different areas and jurisdictions have varying specifics for perc test requirements.

What happens if the soil fails a perc test?

What happens after a failed perc test depends on where you are and the reason the soil failed. Worst case scenario: you may not be able to build at that location. This may be the case if the land is too permeable.

However, if the soil has a percolation rate that is too low (or less permeable), you may have other options. To get excess water off of the land without causing a flood or polluting the groundwater, you may be able to create trenches with additional piping systems.

This is where we come in. Perc tests and land planning should always be left to the experts, and our team of professionals is ready to help you manage the construction process from start to finish. Contact us today to begin.

Leave a Reply